Sighting apparatus for guns.



A. T. DAWSON & G. T. BUGKHAM.

SIGKTING APPARATUS FOR GUNS.

APPLIOATIOI FILED JUIS 1, 1901. Patented 22 A. T. DAWSON 8: G. T. BUGKHAM.

smn'rme APPARATUS r01; owns.

APPLIOLTIOI TILED JUNE 1, 1907.

Patented Sept. 22, 1908. 7

Ii O

UNITED STATES PATENT OFFICE.

ARTHUR TREVOR DAWSON AND GEORGE THOMAS BUCKHAM, OF WESTA'IINSTER, LONDON,

ENGLAND, ASSIGNORS 'IO VICKERS SONS & AXIM LIMITED, OF LONDON, ENGLAND,

SIGHTING APPARATUS FOR GUNS.

Specification of Letters Patent.

Patented Sept. 22, 1908.

Application filed June 1, 1907. Serial No. 376,813.

1 '0 all whom it may concern:

Be it known that we, Aa'rnun Tnsvoa Dawson, lieutenant Royal Navy director and superintendent of Ordnance W orks, and (n-10am: THOMAS BUCKHAM, engineer, both subjects of the King of Great Britain, residing at 32 Victoria street, Westminster, in the county of London, England, have invented certain new and useful Improvements in Si hting Apparatus for Guns, of which the fo lowing is a specification.

This invention relates to sighting apparatus for guns, and has for its chief ob ect to enable corrections to be made in the sighting in order to com )ensate for the variations that arise from the lall in muzzle velocity due to re )eated firin of the gun and also those that arise from diiTerences in the temperature of the charges resulting from the climatic conditions, as regards heat and cold, which provail at (lillerent parts of the globe.

The principle upon which our apparatus is constructed is that the alteration in the range for given elevation of the gun is proportional to the alteration in muzzle velocity and also to the variation of the normal temperature of the charges. For instance at a given elevation of the gun the decrease in range, due to a diminution of a given number of foot-seconds, is ap roximately twice that which is due to a diminution of half that number of footflseconds.

For the purpose of our invention we employ in conjunctipn with the range dial a cam which by means of suitable earing receives motion from the range dial and is adapted to transmit angular movement to the range pointer through the intervention of suitable mechanism which is capable of being set to compensate for the aforesaid variations in the muzzle velocity and the temperature of the charges.

According to our invention, when a plied to si hting apparatus of the kind in w uch a spira ly grooved range dial and a radially movable pointer are employed, the cam is adapted to make one complete revolution for the maximum elevation of the sight and is adapted to act, throu h the intervention of a re ler, upon a lever w iich is capable of looking about a suitable ivot. T is said guide in which the aforesai pointer moves by the action of the spiral groove in the dial is adagted to receive angular displacement about t 10 axis of revolution of the said dial, by the movement of the cam-actuated lever about its pivot, this movement being transmitted through suitable gearing.

In order that our said invention may be clearly understood and readily carried into ellect we will describe the same more fully with reference to the accompanying drawin s, in which *igure 1 is a front elevation of our improved apparatus applied to sighting apparatus of the kind above stated. Fig. 2 is a side elevation of the same as seen from the right of Fig. 1. Fig. 3 is a front elevation of the adjustable pivot about which the aforesaid cam-actuatcd lever rocks. Fig. 4 is a vertical-section of said pivot taken on the line 1-1 of Fig. 3.

A is the range dial, and A its graduated spiral groove. B is the radially movable pointer that en agcs with the said 5 iral groove in the wel known manner and is the guide in which said pointer moves during the revolution of the dial.

C is the cam, D the lever actuated thereby, and E the pivot about which said lever roc s when thus actuated. The said cam C is arranged with its axis of revolution parallel tothe axis of revolution of the range dial A. By means of ear wheels a, a, a. the said cam is adaptet to revolve once for two and one-sixth revolutions which the range dial is (in the example shown) intended to perform durin the maximum elevation of the sight. The t new of this cam for any elevation of the si ht is proportional to the angle subtende on the ran 0 dial by the decrease in range due to a falT of a: foot seconds in the muzzle velocit Carried by a frame or bracket F is he slotted lever D which is adapted to be rocked about the adjustable pivot E by the action of the said cam C u on a roller D situated at the contiguous cm of the lever and constantly kc it pressed against the cam by a spring I). he said lever has hinged thereto a rack d which, under the influence of a spring (1, is kept in engagement with a toothed sector (1. This sector together with the pointer-nude B, is free to swing about the axis 0 revolution of the range dial. The said bracket F to which the lever D is pivoted is furnished with a stop-pin j against which said lever bears when in the iosition indicated in the drawings. The

racket F is provided with two sets of graduatlons or sea-lesfflj, the former being arations inmuz e velocity and is'so constructed that if the adjustable pivot E 'of the said 1 slotted lever D is shifted along this scale, the

, iven decrease in muzzle velocity.

movement imparted b the cam C to the said toothed sector (1' an conscquently to the pointeride B is equal to the angle subtended y the alteration in range for ltile 1e ower scale f indicates the alterations reuired for changes in the temperature of the c iarges and is so arranged tiat successive graduations or markings denote equal differences of item )erature. 'lhe aforesaid adjustable pivot t is mounted in a slide e havmg a pointer e which is ca )able of movement along the temperature sea of when the said pivot E is moved along the slotted lever D. l lovable with the said pivot E is also another slide e having a ointer a capable of movement on the muzz e velocity scale f and this last mentioned slide is also formed with a slot e to render it capable of small lateral locity and a known variation in the tempera- I ture of the charge the muzzle velocity slide e" and the adjustable pivot E are set into the proper position relatively to the muzzle velocity scale so as to indicate the alteration in the muzzle velocity. The said pivot E is then moved inde endently of the muzzle velocity slide to shift the temperature slide a along the temperature scale f it being understood that the direction of movement of said tem erature slide will be towards the cam C if t is temperature is above the normal and in the opposite direction if the tem )erature is below the normal. The aforesai setting ofthe slides and pivot having been offected the parts are clamped by nuts e e on the said pivot or by other appropriate means; it will of course be understood that the amplitudeof movementof the leverD about its pivot E when actuated by the camOis reater or 1653 according as said pivot E is shi ted towardsorfawa from the cam 0, whereby a corresponding ygreateror less angular movement is imparted to the pointer guide B and its pointer B.

Althoughwe have described our invention with particular reference to sighting ap aratus in which a spirally grooved range dia and radially movable pointer are emplo ed we wish it to be understood that the sai invention is applicable to other forms of sighting a paratus in which a range dial and disp aeeable pointer are em loyed.

, What we claim and (esire to secure by Letters Patent of the United States is 1. In un sighting apparatus, the combination with the range dial and its pointer, of a cam o crating in conjunction with the range dia mechanism for transmitting angular motlon to the pointer from the cam, and means for enabling said mechanism to be set to compensate for variations in shooting due to atmospheric influence and to changes in the muzzle velocity.

2.- In gun sighting apparatus, the combination with the range dial and its pointer, of a cam o er'ating in conjunction with the range dia a lever for transmitting angular motion to the pointer from the cam, and means for varyin the degree ofmovement transmitted by said lever from the cam to the pointer.

3. In a gun sighting a paratus, the combination with the range ial and its pointer, of a cam operating in conjunction with the range dial, a lever for transmitting angular motion to the pointer from the cam, and means for varying the amplitude of movement of said lever about its fulcrum.

'4. In gun sighting a paratus, the combination with the range ml and its pointer, of a cam operating in conjunction with the range dial, a lever for transmitting angular motion to the pointer from the cam throu h suitable gearing, and means for enabling t 10 fulcrum of the lever to be shifted toward or away from the said cam and set in relation to suitable scales. In testimony whereof we allix our signatures in rescnce of two witnesses A THUR TREVOR DAWSON.

GEORGE THOMAS BUCKHAM. Witnesses:

HENRY KING,

E. E. Lamcms. 

